1) Start WER in offline mode (there is a separate application called Wizards Event Reporter Offline). Then, if you cannot see the prerelease tournament, simply create a new tournament and run your prerelease in that tournament.Next week, export that event as a .wer-file, and send it to your WPN Rep (http://wpn.wizards.com/en/contact-us) together with the sanctioning ID of the prerelease that it is replacing. You can find the sanctioning ID of a tournament when you open that tournament on the 'Event' tab.

2) If 1) does not work, disconnect the PC that WER is running on from the internet completely (disable wireless and remove the network cable), then try again. WER tries to communicate with the servers even in offline mode. Then proceed as in 1).Yes, this makes no sense. But hey, WER.

3) If neither works, I suggest using TiebreakerJS (full instructions here: http://www.mtgthesource.com/forums/show ... nt-manager). This is a web-app that runs swiss-style tournaments (like your prerelease is) in a very simple and easy-to-use fashion. Make sure to save all info (who played whom in which round) so you can send it to your WPN rep later.